1. Field--The invention relates to medium power near infrared diode lasers, for example, as used in light pumps for Nd:YAG type near infrared lasers.
2. Prior Art--in order to produce a compact pump for a near infrared laser, the pump having a well collimated infrared (IR) beam of substantial cross-section and power density; it has been the practice to mount a plurality of planar diodes parallel to and near edge of a fin-like heat sink member. The diodes are made long and narrow to direct lasing along a preferred axis. One end is coated with a multilayer dielectric mirror to direct the laser output in one direction along preferred axis. The diodes are aligned so that the output beams are parallel and normal to the edge. The diodes on each heat sink are connected in parallel and the sink-diode structures stacked in series to provide a compact two dimensional array and such that the small current and voltage requirements of each diode are multiplied to better match the characteristics of existing power supplies.
The above arrangement has a number disadvantages. The multilayered mirror is expensive and difficult to manufacture. The diode is capable of only about half the peak power as when emission is permitted from both small ends or facets, since the power per facet is limited by catastrophic degradation. The heat sink geometry produces a large temperature gradient between the emitting facet and the dielectric mirror placing undesirable stresses on the diode structure. An object of the present invention is to provide a more efficient arrangement which reduces the stress on the diodes and/or requires fewer diodes for the same output fluence.